That is my dilemma:
Whether 'tis nobler to be portable and ready
And opt for mobility at a price,
Or to remain steadfast and build a tower unit,
One that is upgradeable and cheaper. To build: at cheap;
An updated PC; for which I can run the latest games
And kick Greg's ass at Splinter Cell
And probably UT2k7 when that comes out
Though he's good those games. To build: at cheap;
At cheap: one that would cost only $800: a bargain;
And when Spore comes out I can max out the detail
And play Company of Heroes in hi-res.
Must give us pause: which do I choose?
The laptop for ease of transport to
Ever decreasing LANs, or keep with tradition
And build the bastard with my bare hands.

Sorry about the abhorrent placement of punctuation, stupid Shakespeare.

Laptops are mighty powerful today. So I think instead of thinking "Expensive and portable vs. Cheap, non-portable and powerful" it should really just be "Expensive and portable vs. Cheap and non-portable"

Desktops certainly are more upgradeable though.

Personally, I'd stick with a desktop, but get a nice light aluminum case with only 1 (big) hard drive. Get the smallest size tower you can get (but not a shuttle so you can get a good mobo) - You'll have pretty easy transportation for LANs, but of course you won't be able to take it to bed with you.

If they were the same price, I would get a laptop for sure, even if desktops are more upgradeable.

I'm insulted. The newer shuttles are sucking in terms of part/service quality from what I've heard, but my little things are not only still working fine, but have both been overclocked. Aside from the built-in sound cards (which always suck), the other components have worked fine.

I would steer clear of shuttles as well, since I have heard too many horror stories as of late. Microsoft and Apple-esque 'yeah, we fixed it' stuff, and it comes back as broken as it was when sent off...

Tragedy is when I cut my finger, comedy is when you fall down an open manhole and die. -- Mel Brooks

Go the route I went and buy a white-box DIY laptop from MSI. You can get a system that's still pretty close to top-of-the-line (Dual core and an x1600 or GeForce 7600+) for under $1500. The processors are upgradeable and graphics card companies are making external enclosures for desktop cards that you can hook up through an Express slot in a laptop, so you get desktop performance at home, but mobility everywhere else.